The present invention relates generally to high voltage power supply systems, and more specifically to a high voltage pulse detector capable of measuring pulse top voltage perturbations more than 100 dB down from the pulse height.
Phased array radar and communication systems have transmitters that modulate high voltage (0.1 to 30 KV) pulses to emit electromagnetic radio frequency (RF) signals. Needless to say, the quality of these high voltage pulses is important to the users of these systems, but the measurement of voltage perturbations on the top of high voltage pulses has some inherent difficulties.
The previous methods of measuring voltage perturbations on the top of transmitter modulator high voltage pulses is as follows. In the past, inter modulation products attributed to transmitter modulator pulse amplitude variations were detected in the RF spectrum after the transmitter was designed. This was particularly true when spurious content was required to be down more than one hundred dB. Pulse instrumentation was limited to the use of high voltage probes or voltage dividers. The Tektronix Oscilloscope type Z differential comparator head provided viewing windows in the millivolt range. Later the type Z plug-in was superseded by the type 7A13 differential head used with the Tektronix 7000 Series Scope. The new wideband head provides a resolution of one millivolt for 10 volt pulses and 10 and 100 millivolts, respectively, when ten-to-one or one-hundred to one probes are used.
The storage scope facility (the oscilloscope combined with voltage dividers) provides an excellent basis for pulse top amplitude measurement. The accuracy, however, is limited by the calibration of the resistor divider or step-down probe which are required for voltages in excess to 40 volts. When high-level pulses are measured, induced voltages resulting from radiation often distorts the waveform viewed. Radiation entering through the scope shield can be controlled by moving the scope to a remote location. Radiation introduced in the probe or voltage dividers, however, cannot be suppressed without lowering the source impedance.
In view of the foregoing discussion it is apparent that there remains a need to provide a new means for precision measurement of measuring voltage perturbations on the top of high voltage (0.1 to 30 KV) pulses. The present invention is intended to satisfy that need.